Human Population Growth and Climate Change

Since I first published this page in 2011 the environment has continued to change. For example, the atmosphere has gone past the 350 parts per million of CO2 that scientists define as the upper end of the “normal” range, to 400 parts per million. Data also show the atmosphere warming faster than earlier models predicted.

The increase in world gross domestic product (GDP) is the primary driver to climate change. Although GDP started growing at a faster rate soon after 1750, it began accelerating at a much faster rate by 1986. Our ability to produce more food, shelter, clothing, housing, etcetera enabled our population to grow at an ever increasing rate, shown with the world population growth curve.

The result has been a gradual increase in global temperatures since 1880 (nearly 1° C, 2° C is considered a threshold to drastic climate change). By the mid-sixties, the globe started heating at much faster rate, shown by the Global Land-Ocean Temperature Change Index (the green bars represent the 95% confidence limits for temperature estimates in each of the three periods). However, the sub-arctic and arctic regions are warming at a much faster rate, contributing to sea-level rise and the expected release of large amounts of methane from melting permafrost.

The population growth curve is probably the pre-cursor to a spike, meaning a sharp population drop (though not necessarily all the way down to pre-1750 levels). The planet simply cannot sustain 7+ billion people. This is due to the fact that to sustain current and even larger future populations requires ever more industrial production, which requires dwindling resources that pollute the planet, and threaten a wide array of species (we’re currently in what biologists refer to as the 6th extinction).

Other scientific evidence confirms this, as documented in a recent report released by the National Academy of Sciences. Native Peoples around the world knew they had to live in concert with the environment. With the advent of the modern Europeans, and a philosophy that supported mercantile and industrial expansion, this link with the environment was broken. This philosophy of industrial growth spread to the Western countries, and more recently, to many developing countries.

If our descendants are to survive, we must begin a generations slow process of scaling back industrial production. A tall order, indeed.